Accelerated process for bodying



ACCELERATED PROCESS FOR BODYING VEGETABLE DRYING OILS Donald F.Koenecke, Elizabeth, and Marvin H. Malian,

Roselle, N. l, assignors to Esso Research and Engineering Qompany, acorporation of Delaware No Drawing. Application July 16, 1949, SerialNo. 105,261

2 Claims. or. 106-265 This invention relates to an improvement in dryingoils and more particularly to an improvement in accelerating the heatbodying rate of vegetable oils without depreciating the drying rate orfilm forming properties of the product.

When vegetable oils such as linseed oil are cooked to increase theviscosity in customary manner, a reaction time of about 12 hours isrequired to effect the change. The temperatures necessary for thispurpose are in the range of 295 to 305 C., and the conventional heatingprocedure is therefore usually accompanied by an undesirable darkeningof the treated oil as well as an appreciable loss of material due to theextended cooking. Attempts have been made in the past to increase thelow rate of production and to reduce the concomitant degradation of theoil. These previous attempts have been centered on the use of reactivemonomers such as styrene, butadiene, cyclopentadiene, or of catalystssuch as oxygen or litharge, but in varying degrees the use of any ofthese materials meant a high loss or an impair ment of drying rate,color or some other property of the eventual product. Thus theimprovement in cooking rate was obtained only at a serious sacrificewhich could not always be afforded depending on the vegetable oil usedand the ultimate use contemplated therefor.

it has now been discovered that certain synthetic oily polymers ofdiolefins have a surprisingly beneficial accclerating effect on thecooking rate of vegetable drying oils without causing loss of color andoften actually causing an improvement in hardness and other properties.

Vegetable drying or semi-drying oils to which the present invention isapplicable include linseed oil, soybean oil, rapeseed oil, tung oil,cottonseed, perilla, oiticica, corn, dehydrated castor, fish oil,sunflower seed, safflower and other vegetable oils containing asubstantial proportion of glycerides of linoleic and/or linolcnic acid.

The synthetic oils useful for catalyzing the cooking re action inaccordance with the present invention are oily polymers of butadiene,isoprene, dimethyl butadiene, piperylene, methyl pentadiene or otherconjugated diolefins having four to six carbon atoms per molecule.Instead of polymerizing any of the aforesaid diolefins alone, they maybe copolymerized in admixtures with each other or in admixtures withminor amounts of ethylenically unsaturated monomers copolymerizabletherewith, e. g., with to of styrene, styrenes having alkyl groupssubstituted on the ring such as para methyl styrene, dimethyl styrene ordiethyl styrene, acrylonitrile, methacrylonitrile, methyl acrylate,methyl methacrylate, vinyl isobutyl ether, methyl vinyl ketone, andisopropenyl methyl ketonc. Such synthetic oils may be advantageouslyprepared by mass polymerization either in the presence of a hydrocarbonsoluble peroxide catalyst such as benzoyl peroxide or cumenehydroperoxide, or in the presence of metallic sodium when the monomersconsist of a diolefin or of a mixture of a diolefin with a styrenecompound. Suitable polymerization procedures iii) "ice

' and unreacted butadiene is allowed to volatilize from the polymerizedmixture at 70 C. The resulting product, which is a clear, Water-whitesolution, consists typically of about 60 parts of oily polymer ofbutadiene, about 4 parts of butadiene dimer, plus solvent and somet-butyl alcohol. This solution of polymer is then preferablyfractionated to remove the dimer and usually adjusted to 50%non-volatile matter content. The non-volatile constituent, which is theoily polymer of butadiene, has a molecular weight between 1,000 and10,000, preferably between 2,000 and 5,000. It will be understood, ofcourse, that the foregoing procedure is only illustrative and that itcan be modified in many ways, particularly as described in U. S. patentapplication Serial No. 782,850 of Arundale et al., filed on October 29,1947, which describes alternative monomers, catalysts, reactiondiluents, polymerization modifiers, suitable ranges of proportions ofthe various ingredients, suitable ranges of polymerization conditions,etc.

Run B.-An alternative polymerization method using sodium as catalyst isillustrated as follows 80 parts of butadienel,3, 20 parts of styrene,200 parts of straight run mineral spirits boiling between 150 and. 200C., 40 parts of dioxane, 0.2 part of isopropanol and 1.5 parts of finelydispersed sodium are heated at about C. in a closed reactor providedwith an agitator. Complete conversion is obtained in about 4.5 hourswhereupon the catalyst is destroyed by adding an excess of isopropanolto the polymerized charge. The crude product is cooled, neutralized withcarbon dioxide or glacial acetic acid or the like and filtered. Thecolorless filtrate is then fractionally distilled to remove the alcoholand modifiers such as dioxane. Finally, additional hydrocarbon solventis preferably distilled off until a product containing about 50%-95%non-volatile matter is obtained, the non-volatile matter being a dryingoil having a molecular weight below 10,000, preferably between about2,000 to 5,000.

Again it will be understood that the described sodium polymerizationmethod may be varied considerably as by omitting the styreneco-reactant; or by adding the styrene only after the polymerization ofbutadiene monomer had begun; or dioxane may be replaced by 10 to 35parts of another ether modifier having more than 2 carbon atoms such asmethyl ethyl ether, or the modifier may be omitted altogether,especially when it is not essential to obtain a perfectly colorlessproduct. Similarly, isopropanol is not necessary, though aliphatic alcohols of less than 6 carbon atoms generally have the beneficial effectof promoting the reaction when present in amounts ranging from about 2to 50% based on the weight of sodium catalyst. Furthermore, the mineralspirits may be replaced by other inert hydrocarbon diluents boilingbetween about 15 C. and 200 C., e. g., butane, benzene, xylene,cyclohexane and the like. The diluents are usually used in amountsranging from 50 to 500 parts per 100 parts of monomer. The reactiontemperature may vary between about 40 C. and 100 C., preferably aroundto C. As a catalyst, 0.1 to 10 parts of dispersed metallic sodium isused per parts of monomers, sodium particle sizes below 100 micronsbeing particularly effective.

In general the synthetic drying oils useful for catalyzing the cookingrate of vegetable oils in accordance with the present invention can becharacterized as being stable up to a temperature of about 305 C.

The following examples will serve to illustrate the mode of operation aswell as the advantages of the present invention, though it will beunderstood that various other embodiments or modifications notspecifically illustrated herein are possible without departing from thespirit or scope of the invention. For instance, insteady of co-reactingthe vegetable drying oil with the synthetic drying oil in anon'catalytic thermal process, the heat bodying reaction may be furtheraccelerated by operating in the presence of a suitable catalyst, e. g.,fullers earth or other active clays.

EXAMPLE 1 UCSI Gardner color 1011. Gardner viscosity Z3-Z4 (54 poises).Cure point 117 seconds.

1 Gel time of a thin film on a 200 C. hot plate.

A 50% solution of this heat bodied oil of the invention was prepared bymixing it with an equal amount of straight run mineral spirits boilingbetween 150 and 200 C. (Varsol No. 2), and its air drying rate wascompared with a solution prepared by mixing the same solvent with anequal amount of a commercial bodied linseed oil containing about 10% oftung oil. The commercial oil had the following characteristics:

Gardner color 7. Gardner viscosity Z2 (36.2 poises). Cure point 152seconds.

In evaluating the drying rates of the two oil solutions, 0.5% lead and0.05% manganese in the form of naphthenates were added thereto and thesolutions were then poured on tin plate panels. The results obtained areindicated below, the drying rate being measured on an arbitrary scalewhercon represents a completely tackfree film, 6 represents a film setto touch and 3 represents a film which is dust-free.

1 2 4 7. 5 24 Sample Hr. Hrs. Hrs. Hrs. Hrs.

Invention 4-5 2 1 1 0 Commercial Oil l 1 1 0 It will be observed thatdespite the relatively short bodying period the oil processed inaccordance with the invention had a drying rate which was only slightlyslower in the initial three hours, but caught up with the commercial oilthereafter. Both oils baked satisfactorily in one hour at 120 C. withthe same drier present. A comparison of the properties of air dried and.baked films summarized in Table I below indicates that the two oils werevery nearly equivalent to each other when air dried and also when baked.

All evaluations of film resistance described in this specification havebeen determined as follows:

Water resistancc.-A piece of filter paper was placed on top of thetested film and a small amount of water dropped on the paper. The wetpaper was left in contact with the film for 5 hours.

Soap resista izce.A drop of 2% solution of commercial sodium soap wasformed on a filter paper lying on top of the tested film and the wetpaper left in contact with the film for 2 hours.

Grease rerisrrmce.A piece of filter paper saturated with a 50 mixture ofbutter and oleic acid was left in contact with the film for 2 hours.

Caustic resistance.-A piece of filter paper on which a drop of a 1%aqueous solution of NaOH had been dropped was left in contact with thetested film for one hour.

EXAMPLE 2 Run I.600 parts of alkali-refined linseed oil were graduallyheated to 295 C. over a period of one hour, held at that temperature fortwo hours under a blanket of carbon dioxide while stirring and finallycooled slowly to room temperature.

Run II. 540 parts of alkali-refined linseed oil were blended with asolution containing parts of the polybutadiene oil described in Example1 and 74 parts of a straight run mineral spirits boiling between and 200C., and the blend was seated at 295 C. on the same heat cycle asdescribed in run I above. The mineral spirits were boiled ofi.

Run III.A mixture having the same composition as r in run II wasgradually heated to 260 C. Over a period of about 45 minutes and held atthat temperature for 2 hours.

An evaluation of the three oils cooked as just described is given inTable H:

1 Exclusive of the mineral spirits solvent.

Comparison of runs I and II shows that the addition of synthetic dryingoil causes the natural oil to body more intensively than when nosynthetic oil is present during the heating under the same conditions,and the cooking loss is reduced by almost one half when the syntheticoil is present. Furthermore, the viscosity data indicate that the samedegree of bodying as was obtained in run I can be obtained atsubstantially lower temperatures when the synthetic oil is present, andby this expedient the cooking loss can be reduced still further asillustrated by run Ill. An interpolation of the tabulated data indicatesthat a bodied oil as viscous and also otherwise at least as good as theproduct obtained in one hour at 295 C. by the prior art method can beobtained in accordance with the invention in the same length of timearoeeaa 1 u at a temperature of about 275 C., resulting not only in aconsiderable saving in thermal energy but also in a very importantreduction of the cooking loss down to about 1% of the drying oilcharged. Alternatively, instead of reducing the cooking temperature, theaddition of the synthetic oil allows the cooking step to be carried outin a shorter time span at the same temperature than is possible in theabsence of the synthetic oil. At the same time the possibility ofoperating at lower temperatures or for shorter times is responsible foran improvement in color. All of the foregoing is characteristic of theunexpected advantages of the novel cooking process. That the latter doesnot impair the properties of the vegetable oil or of the dried filmsprepared therefrom but actually improves the hardness and occasionallyalso other properties of the films is shown by the following dataobtained on films cast on tirn plate panels in the presence of 0.5 leadand 0.05% manganese napthenate drier.

*Code: unaffeoted 01 excellent; 9failure.

EXAMPLE 3 in this example a polybutadiene oil prepared in the presenceof sodium catalyst was used to accelerate the heat bodying of avegetable drying oil. The synthetic oil used was prepared substantiallyas described in run B given earlier herein, except that styrene wasomitted from the polymerization mixture and instead a solution of abutadiene homopolymer in mineral spirits was prepared and after theusual finishing steps reduced by distillation to a 50% non-volatilematter content.

For comparison, two linseed oil samples were heated to 295 C. and heldat that temperature for three hours on the same heat cycle. in run Illrepresenting the prior art, 300 g. of alkali-refined linseed oilwereheated in the absence of any added materials whereas in run IVillustrating the invention 30 g. of the polybutadiene oil dissolved inan equal amount of mineral spirits were added to 300 g. of the samelinseed oil. The color and viscosity of each batch were determinedduring the cooking step at one hour intervals and the following resultswere obtained:

CHANGES IN COOKING STEP It will be noticed from the above that the heatbodying in run IV, which illustrates the invention, occurs at a verymuch faster rate than in run III and by interpolation it can be seenthat the viscosity stage reached in run IV after about 70 minutes isequivalent to the stage reached in run III after three hours. Thisnecessarily results not Air Dried (48 hours) Baked (1 hr. C.)-Resistance to- Resistance to Sample Water Soap Grease NaOH Water SoapGrease NaOH Run III", 0 8 3 7 0 5 9 9 Run IV. 4 8 3 8 0 0 0 2 Again itis seen that the air dried films from the oil treated in accordance withthis invention are approxi mately equal to the conventionally treatedoil except for a slightly inferior resistance to water. On the otherhand the baked film from the oil treated according to the invention wasdecidedly superior to the prior art oil in terms of resistance to soap,grease and alkali. Otherwise there was no difference in physicalproperties, all of the tested films being completely tack-free andperfectly flexible as determined by bending the coated steel panelsthrough a 180 degree angle. Both air dried films were slightly softafter 48 hours, but both baked films were firm.

EXAMPLE 4 The present invention is also applicable to oleoresinousvarnishes. T his is illustrated by the following runs V and VI whereinthe reactants indicated in the subjoined formulas were heated in l-gal,stainless steel kettles to 295 C. on the same time-temperature curveunder a carbon dioxide blanket with frequent stirring. After thetemperature of 295 C. was reached, each varnish was held at thattemperature until the cure time of a thin film on a 200 C. hot plate wasbrought down to 4045 seconds. Thereafter each kettle was quenched inwater and the oleoresinous varnish was diluted with an equal weight ofstraight run mineral spirits boiling between and 200 C. (Varsol #2).

Cooking observations:

Run V Run VI Cook time, hours ,0. 3:00 5:02 Cook loss, weight percent-8.1 10.1 Viscosity, poise. 4. 85 2.12 Color, Gardner; 13 17 It will benoticed that the cook time required to produce a varnish of equivalentcure time can be reduced by about 40% in accordance with the presentinvention. As a consequence of this reduced cooking time the cook lossis also reduced appreciably and acooked varnish of lighter color isobtained.

When 0.5 weight percent of lead and 0.05 weight per cent of manganese inthe form of naphthenates were aroaeea l added to each of the cookedvarnishes and the latter applied to tin plate panels, films having thefollowing properties. were obtained:

295 C. under a carbon dioxide blanket with frequent stirring andmaintained at that temperature until the cure time of a thin film of thevarnish base on a 200 *Oode: Unaffected; 3-4appreciable softening;9-failure.

It will be noticed that the films resulting from the varnish processedaccording to this invention were substantially equivalentto the priorart product in all properties tested.

The accelerated varnishes of this invention can also be usedsuccessfully in the preparation of enamels. For example a white enamelwas prepared from the varnish obtained in run V by mixing to a smoothpaste 245 g. of titanium dioxide pigment and 200 g. of the varnish andgrinding the paste to enamel particle size on a pigment roller mill. Theresulting paste was mixed further with an additional 400 g. of the samevarnish, g. of 16% lead and 1% of manganese drier (the drier being asolution of metal naphthenates in xylol) and 7.5 g; of 2% cobaltnaphthenate drier. In a control run the same procedure was followedusing the varnish produced in run VI. Both enamels dried satisfactorilywhen applied by brushing or spraying and the resulting films were hardand glossy. In order to compare their weathering characteristics, twocoats of each enamel were sprayed on primed bonderized steel panelswhich were then exposed to the conditions of an Atlas Weather-O-Meterfor 600 hours, said to be the equivalent of 600 days of exterior 4 Bothwhite enamels behaved the same way exposure. in that they lost gloss toan eggshell appearance and displayed some mierocracking at the end ofthis rather severe test period, showing that the accelerated heatbodying. treatment of this invention has no adverse affect on theproperties of the resulting enamels. Similar results were also obtainedwith red enamels containing toluidine red pigment, both the acceleratedand the unaccelerated enamel showing equal fading after 600 hoursexposure in the Weather-O-Meter.

EXAMPLE 5 In this example the accelerating effect of a polybutadiene oilwas tested in connection with an oleoresinous varnish base containing asynthetic all-hydrocarbon resin prepared by copolymerization of 55 partsbutadiene and parts of diisobutylene at -l5 C. with aluminum chloridecatalyst, as described in U. S. patent applications Serial No. 610,211,filed August 10, 1945, and Serial No. 638,514, filed December 29, 1945.

In each run all the reactants specified above were placed in al-gallonstainless steel kettle, heated to C. hot plate was reduced toseconds. Thereafter the kettle was quenched in water and the varnishbase mixed with an equal weight of straight run mineral spirits.

Results:

Run VIII Cook time, hours... 3:12 Viscosity. poise Gel EXAMPLE 6 In thisexample the accelerating efiect of a butadienestyrene copolymer oil wastested in connection with an oleoresinous varnish containingalkali-refined soybean oil and a hydrocarbon resin prepared by thecopolymerization of 50 parts of butadiene and 50 parts of xylene at 15C. with aluminum chloride catalyst.

Formulas:

Run IX- Run X 150 g. 232 g. 38.2 g.

hydrocarbon resin alkali-refined soybean oil The specified reactantswere heated in an aluminum kettle under a nitrogen blanket with stirringto 295 C. and held at that temperature until the cure time of a thinfilm of the varnish base'on a 200 C. hotplate was reduced to seconds.Thereafter the varnish base was cooled quickly to 230 C. and mixed withan equal weight of straight run mineral spirits.

Results:

Run IX Run X Cook time, hrs 11. 42 5. 52 Cook loss, wt. percent...- 16.0 11.0 Viscosity, poise 4. 0 2. 4 Color, Gardner 14 12-13 It will benoticed again that the cooking time required for the accelerated varnishis only about one-half that required to polymerize the control varnishto a state characterized by a comparable cure time. Furthermore, inconsequence of the reduced cooking time the amount of valuable oil lostduring the cooking can be seen to have been reduced by about one-third.The color of the cooked accelerated varnish was again lighter than thenon-accelerated varnish.

To show that the cooked accelerated varnish has approximately the samecure time or drying rate as the more viscous product obtained by cookingof the non-accelerated varnish, the products of runs IX and X were mixedwith 0.5% lead and 0.05% manganese naphthenate drier, and coated on tinplate panels and tested.

Air drying rate:

Hours Sample Run IX...

3 1 Run X., 6 3 2 1 1 Rating: 9\\'ct; 6-Scti-Lo-toucl1; 3-dust-tree;0tack-[ree. The properties of air dried and baked films prepared fromeach of the varnishes were also compared:

Film Resistance* to- Flexibility 180 Bend Test Sample Hardness WaterSoap Grease NaOH Air Dried, 1 week Run IX Run X Good...

Unaffected. Do.

Baked, 1 hour 120 C.

Run IX 0 0 Run X 0 0 0 0 Good..- 0 4 Unaifeetod. do. Do.

*Rating: 0-unatlected; 1-3 discolored; 4-6 softened and less adherent;78 pinholed or blistered; 9, film removed.

Again it can be seen that the two varnishes have approximately equalproperties, air-dried films of the accelerated varnish having somewhatsuperior water and soap resistance than air-dried films of the ordinaryvarnish whereas in the baked state films of the ordinary varnish showsomewhat better resistance to alkali than the corresponding filmobtained from the accelerated varnish.

in summary, the invention illustrated by the foregoing examples consistsof accelerating the cooking rate of drying or semi-drying vegetable oilsby adding thereto about 2 to 25%, preferably about to 15% of an oilybutadiene polymer or copolymer and thereafter cooking the mixture insubstantial absence of oxygen at a ternperature of about 230 to 330 C.,preferably 265 C. to 300 C. until the cooked oil has reached the desiredconsistency or cure time. instead of applying the invention to thecooking of vegetable oils alone, it can be applied with equal benefit tothe cooking of oleoresinous varnishes containing a vegetable oil andabout 10 to of a resin such as ester gum, various oil solublehydrocarbon resins, phenolics, modified phenolics, maleictreated rosinsand esters, and natural resins. The principal advantage of the inventionlies in the fact that heat bodying of vegetable oils, which isessentially a polymerization phenomenon, can be accomplished in ashorter time or at a lower temperature or both, and consequently thecook loss as well as the darkening of the valuable charge is kept to aminimum. It follows from the foregoing that the invention ofiersimportant economies in heat, time and material, without in any wayimpairing the properties of the eventual product.

In the course of investigating the present invention, it was establishedthat a substantial preponderance of the vegetable oil over the syntheticbutadiene oil is desirable as far as cooking rate is concerned. At thesame time, however, the discovery was made that if the proportion isreversed as by co'reacting about 70 parts of oily butadiene polymer with30 parts of dehydrated castor oil at 295 C. for eighty minutes,varnishes derived from the resulting base have been found to have anexcellent ability to wet metallic and glass surfaces. This is quitesurprising in view of the fact that, in the absence of vegetable oil,the drying oils synthesized from butadiene have a tendency to creep andcrawl into rivulets, leaving a discontinuous film when applied to metalor glass.

Having fully described the invention and illustrated some of the bestmodes of carrying it out, the following claims are made thereto.

I claim:

1. A process for heating a vegetable drying oil with a synthetic dryingoil which comprises mixing a vegetable oil chosen from the groupconsisting of drying and semidrying oils with a non-volatile oilypolymer of a C4 to Cs conjugated diolefin having a molecular weight of1,000 to 10,000 and being stable up to 305 C. and heating the mixture ata temperature between 230 and 340 2. A process for heating a vegetabledrying oil with a synthetic drying oil which comprises mixing 30 partsof dehydrated castor oil with 70 parts of an oily butadiene polymer andheating the mixture at 295 C. for minutes.

References Cited in the file of this patent UNlTED STATES PATENTS2,443,044 Lycan et al. June 8, 1948 2,476,341 Weber July 19, 19492,523,609 Bloch et al. Sept. 26, 1950 2,581,413 Hillyer Jan. 8, 19522,586,594 Arundale et al Feb. 19, 1952 2,653,956 Marhofer et al. Sept.29, 1953

1. A PROCESS FOR HEATING A VEGETABLE DRYING OIL WITH A SYNTHETIC DRYINGOIL WHICH COMPRISES MIXING A VEGETABLE OIL CHOSEN FROM THE GROUPCONSISTING OF DRYING AND SEMIDRYING OILS WITH A NON-VOLATILE OILYPOLYMER OF A C4 TO C6 CONJUGATED DIOLEFIN HAVING A MOLECULAR WEIGHT OF1,000 TO 10,000 AND BEING STABLE UP TO 305* C. AND HEATING THE MIXTUREAT A TEMPERATURE BETWEEN 230 AND 340* C.